Franz Diffusion Cell System Research Articles

Influence of dietary zinc on the claw and interdigital skin of sheep

Claw diseases like interdigital dermatitis and footrot threaten sheep health and are major welfare issues. Several studies mainly done in cattle suggested that zinc (Zn) supplementation may improve claw integrity. However, Zn supplements may differ markedly regarding Zn bioavailability. Zn bound to single amino acids has been shown to be more bioavailable than inorganic Zn sources. The aim of this study was to determine the effect of different Zn supplements on the integrity of the claw and interdigital skin of healthy sheep. At weaning 30 Merino lambs were randomly allocated to three different dietary treatments which were provided through the pelleted concentrates as follows: 1) no supplemental Zn (Zn0); 2) addition of 40 mg/kg Zn as Zn sulphate (ZnS); 3) addition of 40 mg/kg organic Zn as Zn amino acid complex (CZn). Barley straw and pelleted concentrates were given ad-libitum. The calculated Zn concentration of the total diet (roughage and concentrate) without supplemental Zn (Zn0) was 38 mg Zn/kg DM. The concentrates were formulated to meet the nutritional requirements for growing lambs and contained 207 g/kg DM crude protein and 12.4 MJ/kg DM metabolizable energy. After 8 weeks the lambs were slaughtered and the following specimens were collected: blood serum, liver, sole and coronary band of the claw, and interdigital skin. Serum and tissue Zn and copper (Cu) concentrations and claw hardness were determined. Routine pathohistology and electron microscopy were conducted. Franz diffusion cell system and Ki-67 immunostaining were used to determine the permeability of the interdigital skin and the keratinocyte proliferation in the basal layer of sole horn, coronary band and interdigital skin, respectively. The concentrations of Zn and Cu in serum and liver tissue as well as the Zn concentration in claw horn were not affected by dietary treatment. Zn0 lambs showed higher (p < 0.05) Cu concentrations in claw horn compared to both Zn supplemented groups. Routine pathohistology as well as electron microscopy did not show significant morphological differences between the three groups. Franz diffusion cell system proved to be a suitable method examining the interdigital skin permeability, but the group differences in this study were not significant. Dietary treatment did not affect keratinocyte proliferation in the coronary band. In the sole keratinocyte proliferation was significantly higher (p < 0.05) in the Zn0 group compared to CZn with ZnS being intermediate. Keratinocyte proliferation in the interdigital skin was significantly higher (p < 0.05) in the CZn group compared to the Zn0 with ZnS being intermediate. The results of the current experiment indicate that serum and tissue Zn concentrations and horn hardness are not affected by adding a moderate amount of Zn sulphate or Zn amino acid complex to a basal diet. However, supplemental Zn amino acid complex seems to affect keratinocyte proliferation of interdigital skin and sole horn of lambs. Effects on skin permeability should be retested using a higher number of animals prospectively.

DenTimol as A Dendrimeric Timolol Analogue for Glaucoma Therapy: Synthesis and Preliminary Efficacy and Safety Assessment.

In this work, we report the synthesis and characterization of DenTimol, a dendrimer-based polymeric timolol analog, as a glaucoma medication. A timolol precursor ( S)-4-[4-(oxiranylmethoxy)-1,2,5-thiadiazol-3-yl]morpholine (OTM) was reacted with the heterobifunctional amine polyethylene glycol acetic acid (amine-PEG-acetic acid, Mn = 2000 g/mol) via a ring opening reaction of an epoxide by an amine to form the OTM-PEG conjugate. OTM-PEG was then coupled to an ethylenediamine (EDA) core polyamidoamine (PAMAM) dendrimer G3 to generate DenTimol using the N-(3-(dimethylamino)propyl)- N'-ethylcarbodiimide hydrochloride (EDC)/ N-hydroxysuccinimide (NHS) coupling reaction. MALDI mass spectrometry, 1H NMR spectroscopy, and HPLC were applied to characterize the intermediate and final products. Ex vivo corneal permeation of DenTimol was assessed using the Franz diffusion cell system mounted with freshly extracted rabbit cornea. The cytotoxicity of DenTimol was assessed using the WST-1 assay. Our results show that DenTimol is nontoxic up to an OTM equivalent concentration of 100 μM. DenTimol is efficient at crossing the cornea. About 8% of the dendrimeric drug permeated through the cornea in 4 h. Its IOP-lowering effect was observed in normotensive adult Brown Norway male rats. Compared to the undosed eye, an IOP reduction by an average of 7.3 mmHg (∼30% reduction from baseline) was observed in the eye topically treated with DenTimol (2 × 5 μL, 0.5% w/v timolol equivalent) in less than 30 min. Daily dosing of DenTimol for a week did not cause any irritation or toxicity as confirmed by the histological examination of ocular tissues, including the cornea, ciliary body, and retina.

Mycophenolic Acid for Topical Immunosuppression in Vascularized Composite Allotransplantation: Optimizing Formulation and Preliminary Evaluation of Bioavailability and Pharmacokinetics.

Mycophenolic acid (MPA), is the active form of the ester prodrug mycophenolate mofetil (MMF). MMF is an FDA approved immunosuppressive drug that has been successfully used in systemic therapy in combination with other agents for the prevention of acute rejection (AR) following solid organ transplantation (SOT) as well as in vascularized composite allotransplantation (VCA). Systemic use of MMF is associated with gastrointestinal adverse effects. Topical delivery of the prodrug could thus provide graft-targeted immunosuppression while minimizing systemic drug exposure. Our goal was to develop a topical formulation of MPA with optimal in vitro/in vivo characteristics such as release, permeation, and tissue bioavailability to enable safety and efficacy evaluation in clinical VCA.Permeation studies were performed with a solution of MPA (10 mg/ml). In vitro release and permeation studies were performed for different semisolid formulations (Aladerm, Lipoderm, emollient, and VersaBase) of MPA (1% w/w) using a Franz Diffusion Cell System (FDCS). In vivo pharmacokinetic characterization of MPA release from Lipoderm was performed in rats.MPA in solution exhibited a steady state flux (3.8 ± 0.1 µg/cm2/h) and permeability (1.1 × 10−7 ± 3.2 × 10−9 cm/s). MPA in Lipoderm exhibited a steady state flux of 1.12 ± 0.24 µg/cm2/h, and permeability of 6.2 × 10−09 ± 1.3 × 10−9 cm/s across the biomimetic membrane. The cumulative release of MPA from Lipoderm, showed a linear single-phase profile with a R2 of 0.969. In vivo studies with MPA in Lipoderm showed markedly higher local tissue MPA levels and lower systemic MPA exposure as compared to values obtained after intravenous delivery of the same dose of drug (p < 0.05).We successfully developed for the first time, a topical formulation of MPA in Lipoderm with optimal in vitro/in vivo permeability characteristics and no undesirable local or systemic adverse effects in vivo. Our study provides key preliminary groundwork for translational efficacy studies of topical MPA in pre-clinical large animal VCA models and for effectiveness evaluation in patients receiving VCA.

Inhibition effects of a negative electret 5-FU patch on the growth of a hypertrophic scar

In this study, the hypertrophic scar (HS) model in rats was established. 5-fluorouracil (5-FU) patch, −1000 V and −2000 V polypropylene (PP) electret 5-FU patches were prepared and applied onto the wound. The in vitro permeation experiment was performed using the Franz diffusion cell system to determine the permeation cumulative amount and retention amount of 5-FU through/in scar skin. The inhibition effect of negative electret on growth of HS was studied by hematoxylin-eosin (HE) staining, Masson staining and the immunohistologicall methods. The permeation study indicated that a negative electret could enhance the permeation and retention of 5-FU through and in scar skin respectively. HE staining and Masson staining indicated a better effect for −1000 V and −2000 V electret 5-FU patches on HS inhibition after 28 d post-wounding compared with 5-FU patch. The immunohistological study showed much more reduced expressions of collegan type I, collegan type III, TGF-β1 and HSP47 in scar tissue after application of negative electret 5-FU patches than those of 5-FU patch. A negative electret 5-FU patch may be advantageous for HS treatment.

Dermal uptake and percutaneous penetration of organophosphate esters in a human skin ex vivo model

Organophosphate esters (OPEs) are used as flame retardants, plasticizers, and as hydraulic fluids. They are present in indoor environments in high concentrations compared with other flame retardants, and human exposure is ubiquitous. In this study we provide data for estimating dermal uptake for eight OPEs and ranking in OPEs risk assessment. Dermal uptake and percutaneous penetration of the OPEs were studied in a Franz diffusion cell system using human skin dosed with a mixture of OPEs in an ethanol:toluene (4:1) solution. Large variation in penetration profiles was observed between the OPEs. The chlorinated OPEs tris(2-chloroisopropyl) phosphate (TCIPP), and in particular tris(2-chloroethyl) phosphate (TCEP), penetrated the skin quite rapidly while tris(1,3-dichlor-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP) tended to build up in the skin tissue and only smaller amounts permeated through the skin. For tris(isobutyl) phosphate (TIBP), tris(n-butyl) phosphate (TNBP), and tris(methylphenyl) phosphate (TMPP) the mass balance was not stable over time indicating possible degradation during the experimental period of 72 h. The rates at which OPEs permeated through the skin decreased in the order TCEP > TCIPP ≥ TBOEP > TIBP ≥ TNBP > TDCIPP > TPHP > TMPP. Generally, the permeation coefficient, kp, decreased with increasing log Kow, whereas lag time and skin deposition increased with log Kow. The present data indicate that dermal uptake is a non-negligible human exposure pathway for the majority of the studied OPEs.

Ex vivo studies for the passive transdermal permeation and extent of metabolism of methyl and butyl paraben from a cream

Concerns regarding the safety of cumulative exposure to parabens have been raised as a consequence of their estrogenic and endocrine effects. These antibacterial agents are commonly used in food, pharmaceutical and cosmetic products. Preliminary data from animal models has indicated potential links between paraben exposure and various conditions ranging from skin disorders to autism. Oral consumption of parabens is not a cause for concern because they are readily metabolised by the liver and excreted rapidly by the kidney. The presence of parabens in adipose tissue is thought to be due to dermal absorption of parabens where they are incompletely metabolised. Various studies have been performed on paraben absorption; however transdermal permeation of parabens from an emulsion has not been studied to date. In this preliminary study dermal permeation and metabolism across human skin were evaluated for methyl paraben (MP) and butyl paraben (BP) from an emulsion, using Franz Diffusion cell system with analysis by q-ToF (quadrupole time of flight) mass spectrometry. MP was observed to have lower permeation and lower extent of metabolism than BP.

Formulation and in vitro evaluation of carbopol 934-based modified clotrimazole gel for topical application.

The aim of present study was to enhance topical permeation of clotrimazole gel preparation by using various permeability enhancers such as coconut oil, pistachio oil and sodium lauryl sulphate (SLS). Clotrimazole gel preparations were prepared and optimized by using three factor, five level central composite design. A second-order polynomial equation was generated in order to estimate the effect of independent variables i.e. coconut oil (X1), pistachio oil (X2) and sodium lauryl sulphate (X3) at various dependent variables i.e. flux (Y1), lag time (Y2), diffusion coefficient (Y3), permeability coefficient (Y4), and input rate (Y5) of clotrimazole gel formulations. Ex vivo skin permeation study was performed through rat skin by using modified Franz diffusion cell system. Optimized formulation F8 exhibited highest flux 2.17 µg/cm2/min, permeability coefficient 0.0019 cm/min and input rate 1.543 µg/cm2/min, along with moderate lag time 77.27 min and diffusion coefficient 0.063 cm2/min, which is further supported by anti-fungal activity that exhibited more prominent zone of inhibition against Candida albicans, Aspergillus niger and Mucor. Thus, it can be concluded that permeation of clotrimazole gel was enhanced by various combination of coconut oil, pistachio oil and sodium lauryl sulphate but optimized formulation F8 containing 0.4 ml pistachio oil, 0.8 ml coconut oil and 0.04 g of SLS exhibited more pronounced and promising effect through rat skin.

New doxorubicin nanoparticles engineered from calcium-crosslinked carbomer and a microemulsion precursor

The purpose of this study was to investigate a new polymeric system and production process in which self-assembled doxorubicin-loaded nanoparticles were synthetized by using a water-in-oil microemulsion as a template and calcium ions as cross-linkers. The manufacturing process combined cross-linking of carbomer within a W/O microemulsion followed by a phase-separation technique to avoid using organic solvents for extraction. To assess the sustained release behavior of doxorubicin from the nanoparticles, we have developed a new simple method based on the permeability coefficient of a synthetic membrane mounted on Franz diffusion cell system. Franz cells were preferred over the commonly used dialysis tubing because they provide adequate measures of the diffusion area as well as the volumes of the media in both sides of the membrane. The lower permeability values obtained for nanoparticles have shown that the release is a limiting step of the diffusion process, while the calculated straight lines may imply that the apparent release rate of the nanoparticle ensembles is close to a zero-order kinetics. The new drug release method for the evaluation of nano-carriers, utilizing a simple linear model to determine the permeability coefficient, has been proposed for perfect sink and non-sink conditions.

A novel thermo-mechanical system enhanced transdermal delivery of hydrophilic active agents by fractional ablation

The Tixel is a novel device based on a thermo-mechanical ablation technology that combines a sophisticated motion and a temperature control. The fractional technology is used to transfer a very precise thermal energy to the skin thereby creating an array of microchannels, accompanying by no signs of pain or inconvenience. This study aimed to evaluate the effect of the Tixel on the skin permeability of three hydrophilic molecular models: verapamil hydrochloride, diclofenac sodium, and magnesium ascorbyl phosphate. Tixel’s gold-platted stainless steel tip heated to a temperature of 400°C was applied on skin for 8ms or 9ms at a protrusion of 400μm (the distance in which the tip protrudes beyond the distance gauge). The experiments were carried out partly in vivo in humans using a fluorescent dye and a confocal microscopy and partly in vitro using porcine skin and a Franz diffusion cell system. The results obtained in this study have shown that (a) no significant collateral damage to the skin tissue and no necrosis or dermal coagulation have been noted, (b) the microchannels remained open and endured for at least 6h, and (c) the skin permeability of hydrophilic molecules, which poorly penetrate the lipophilic stratum corneum barrier, was significantly enhanced by using Tixel’s pretreatment.

Evaluation of γ-cyclodextrin effect on permeation of lipophilic drugs: application of cellophane/fused octanol membrane

According to the Biopharmaceutics Classification System, oral bioavailability of drugs is determined by their aqueous solubility and the ability of the dissolved drug molecules to permeate lipophilic biological membranes. Similarly topical bioavailability of ophthalmic drugs is determined by their solubility in the aqueous tear fluid and their ability to permeate the lipophilic cornea. Enabling pharmaceutical excipients such as cyclodextrins can have profound effect on the drug bioavailability. However, to fully appreciate such enabling excipients, the relationship between their effects and the physicochemical properties of the permeating drug needs to be known. In this study, the permeation enhancing effect of γ-cyclodextrin (γCD) on saturated drug solutions containing hydrocortisone (HC), irbesartan (IBS), or telmisartan (TEL) was evaluated using cellophane and fused cellulose-octanol membranes in a conventional Franz diffusion cell system. The flux (J), the flux ratio (JR) and the apparent permeability coefficients (Papp) demonstrate that γCD increases drug permeability. However, its efficacy depends on the drug properties. Addition of γCD increased Papp of HC (unionized) and IBS (partially ionized) through the dual membrane but decreased the Papp of TEL (fully ionized) that displays low complexation efficacy. The dual cellophane-octanol membrane system was simple to use and gave reproducible results.

Design of an Inflammation-Sensitive Polyelectrolyte-Based Topical Drug Delivery System for Arthritis.

The most successful treatment strategy for arthritis is intra-articular injections that are costly and have reduced patient compliance. The purpose of the current study was to develop an inflammation-sensitive system for topical drug administration. Multi-macromolecular alginate-hyaluronic acid-chitosan (A-H-C) polyelectrolyte complex nanoparticles, loaded with indomethacin were developed employing pre-gel and post-gel techniques in the presence of dodecyl-L-pyroglutamate (DLP). In addition to in vitro studies, in silico simulations were performed to affirm and associate the molecular interactions inherent to the formulation of core all-natural multi-component biopolymeric architectures composed of an anionic (alginate), a cationic (chitosan), and an amphi-ionic polyelectrolytic (hyaluronic acid) macromolecule. The results demonstrated that DLP significantly influenced the size of the synthesized nanoparticles. Drug-content analysis revealed higher encapsulation efficiency (77.3%) in the presence of DLP, irrespective of the techniques used. Moreover, in vitro drug release studies showed that indomethacin release from the nanosystem was significantly improved (98%) in Fenton's reagent. Drug permeation across a cellulose membrane using a Franz diffusion cell system showed an initial surge flux (0.125mg/cm(-2)/h), followed by sustained release of indomethacin for the post-gel nanoparticles revealing its effective skin permeation efficiency. In conclusion, the study presents novel nanoparticles which could effectively encapsulate and deliver hydrophobic drugs to the target site, particularly for arthritis.

In vitro Dermal Absorption: Sample Application and Seal Quality in a Franz Diffusion Cell System

One of the known drawbacks of in vitro dermal absorption methods is their high interlaboratory variation. Although often attributed to biological skin differences, it has been shown that validation of other parameters such as temperature and stirring speed can reduce the high variability observed. The Organisation for Economic Co-operation and Development (OECD) and, at the EU level, the Scientific Committee on Consumer Safety (SCCS) have published guidance documents of how to perform these in vitro tests. For the parameter ‘sample application' and ‘adequate seal', it is indicated to apply the sample homogeneously and provide an adequate seal between the donor chamber and the membrane on which the sample is applied. Here, a simple and visual densitometer-based method is provided, which makes evaluation possible of any application protocol used.

Improvement of arbutin trans-epidermal delivery using radiofrequency microporation

Purpose: To assess the ability of radiofrequency (RF) microporation to promote trans-epidermal delivery of arbutin.Methods: To investigate the enhancing effect of RF microchannels on skin permeation of arbutin, in vitro skin permeability studies were performed with RF microporation-treated Hartley albino guinea pig skin using Franz diffusion cell system. Furthermore, improved depigmentation effects in brown guinea pig in vivo after treatment with RF microporation was evaluated to create hydrophilic microchannels for arbutin trans-epidermal delivery.Results: RF microporator caused disruption of the stratum corneum (SC) and created 50 μm diameter microchannels at a depth of 100 μm in the skin. RF microporation increased skin permeability of arbutin 2.25-fold compared to untreated skin exposed to RF in vitro. Arbutin administration led to considerable skin depigmentation following RF microporation of UV-induced hyperpigmented skin in a 28-day in vivo experiment (ΔL-value on day 28: UV, 0.17 ± 0.50; UV + RF, 0.07 ± 0.48; UV + arbutin, 1.32 ± 0.51 and UV + RF + arbutin, 1.82 ± 0.53).Conclusion: RF microporation seems to be a suitable physical trans-epidermal delivery technology for topical application of highly hydrophilic depigmentation agents through the hydrophobic skin barrier.Keywords: Radiofrequency microporation, Trans-epidermal delivery, Depigmentation, Arbutin

Use of Curcuma longa in cosmetics: extraction of curcuminoid pigments, development of formulations, and in vitro skin permeation studies

Curcuma longais a ginger family aromatic herb (Zingiberaceae) whose rhizomes contain curcuminoid pigments, including curcumin, a compound known for its anti-inflammatory effects. The objective of this study was to obtain curcuminoid-rich extracts, develop topical formulations thereof, and assess the stability and skin permeation of these formulations. Curcuma longa extracts were obtained and used to develop formulations. Skin permeation studies were conducted in a modified Franz diffusion cell system, and skin retention of curcuminoid pigments was quantified in pig ear membrane. Prepared urea-containing gel-cream formulations were unstable, whereas all others had satisfactory stability and pseudoplastic rheological behavior. The amount of curcuminoid pigments recovered from the receptor solution was negligible. The skin concentration of curcuminoid pigments retained was positive (&gt;20 µg/g of skin, mostly in the stratum corneum), considering the low skin permeability of curcumin. We conclude that development of topical formulations containing curcumin or Curcuma longaextract is feasible, as long as adjuvants are added to improve preservation and durability. The formulations developed in this study enabled penetration of curcumin limited to the superficial layers of the skin and then possibly without a risk of systemic action, thus permitting local use as a topical anti-inflammatory.

Recombinant Human Epidermal Growth Factor (rhEGF)-loaded Solid Lipid Nanoparticles: Fabrication and Their Skin Accumulation Properties for Topical rhEGF Delivery

For the present study, rhEGF was encapsulated into solid lipid nanoparticles (SLNs). The SLNs were prepared by the W1/O/W2 double emulsification method combined with the high pressure homogenization method and the physical properties such as particle size, zeta-potential and encapsulation efficiency were measured. The overall particle morphology of SLNs was investigated using a transmission electron microscopy (TEM). The percutaneous skin permeation and accumulation property of rhEGF was evaluated using Franz diffusion cell system along with confocal laser scanning microscopy (CLSM). The mean particle size of rhEGF-loaded SLNs was 104.00 ± 3.99 nm and the zeta-potential value was in the range of �36.99 ± 0.54 mV, providing a good colloidal stability. The TEM image revealed a spherical shape of SLNs about 100 nm and the encapsulation efficiency was 18.47 ± 0.22%. The skin accumulation of rhEGF was enhanced by SLNs. CLSM image analysis provided that the rhEGF rat skin accumulation is facilitated by an entry of SLNs through the pores of skin.

Efficacy of imiquimod-based transcutaneous immunization using a nano-dispersed emulsion gel formulation.

BackgroundTranscutaneous immunization (TCI) approaches utilize skin associated lymphatic tissues to elicit specific immune responses. In this context, the imidazoquinoline derivative imiquimod formulated in Aldara applied onto intact skin together with a cytotoxic T lymphocyte (CTL) epitope induces potent CTL responses. However, the feasibility and efficacy of the commercial imiquimod formulation Aldara is limited by its physicochemical properties as well as its immunogenicity.Methodology/Principal FindingsTo overcome these obstacles, we developed an imiquimod-containing emulsion gel (IMI-Gel) and characterized it in comparison to Aldara for rheological properties and in vitro mouse skin permeation in a Franz diffusion cell system. Imiquimod was readily released from Aldara, while IMI-Gel showed markedly decreased drug release. Nevertheless, comparing vaccination potency of Aldara or IMI-Gel-based TCI in C57BL/6 mice against the model cytotoxic T-lymphocyte epitope SIINFEKL, we found that IMI-Gel was equally effective in terms of the frequency of peptide-specific T-cells and in vivo cytolytic activity. Importantly, transcutaneous delivery of IMI-Gel for vaccination was clearly superior to the subcutaneous or oral route of administration. Finally, IMI-Gel based TCI was at least equally effective compared to Aldara-based TCI in rejection of established SIINFEKL-expressing E.G7 tumors in a therapeutic setup indicated by enhanced tumor rejection and survival.Conclusion/SignificanceIn summary, we developed a novel imiquimod formulation with feasible pharmaceutical properties and immunological efficacy that fosters the rational design of a next generation transcutaneous vaccination platform suitable for the treatment of cancer or persistent virus infections.

An improved cryopreservation method for porcine buccal mucosa in ex vivo drug permeation studies using Franz diffusion cells

The use of isolated animal models to assess percutaneous absorption of molecules is frequently reported. The porcine buccal mucosa has been proposed as a substitute for the buccal mucosa barrier on ex vivo permeability studies avoiding unnecessary sacrifice of animals. But it is not always easy to obtain fresh buccal mucosa. Consequently, human and porcine buccal mucosa is sometimes frozen and stored in liquid nitrogen, but this procedure is not always feasible. One cheaper and simpler alternative is to freeze the buccal mucosa of freshly slaughtered pigs in a mechanical freezer, using DMSO and albumin as cryoprotective agents. This study compared the ex vivo permeability parameters of propranolol hydrochloride through porcine buccal mucosa using a Franz diffusion cell system and HPLC as detection method. The freezing effects on drug permeability parameters were evaluated. Equally histological studies were performed. Furthermore, the use of the parameter transmucosal water loss (TMWL) as an indicator of the buccal mucosa integrity was evaluated just as transepidermal water loss (TEWL) is utilized for skin integrity. The results showed no difference between fresh and frozen mucosal flux, permeability coefficient or lag time of propranolol. However, statistical significant difference in TMWL between fresh and frozen mucosa was observed.

Diffusion of jojoba oil microencapsulated and impregnated onto compressive garment through a pig skin

Scientific developments are in progress in order to create compressive fabric in the medical field. This study focused on the development of a compressive garment in polyamide designated for severe burns in terms of pressure and hydration release. The fabric was then enhanced by adding a moisturizing treatment. The improvement consisted of the impregnation of ethylcellulose microcapsules containing jojoba oil on the textile surface of compressive garment. The kinetic of release of this active ingredient from the microcapsules, as well as its diffusion through the skin, were assessed using the in vitro Franz diffusion cell system. The results showed a controlled release of jojoba oil over time. The amount of oil released during the experiments (168 h) and that which penetrated through the pig skin did not exceed 1% of the total amount of jojoba oil microencapsulated and impregnated on the surface of a compression garment. This study permitted to obtain a compressive garment which presents hydration properties.

Development and in vitro evaluation of a nanoemulsion for transcutaneous delivery

Objective: The purpose of this study is to develop a nanoemulsion formulation for its use as a transcutaneous vaccine delivery system.Materials and methods: With bovine albumin-fluorescein isothiocyanate conjugate (FITC-BSA) as a vaccine model, formulations were selected with the construction of pseudo-ternary phase diagrams and a short-term stability study. The size of the emulsion droplets was furthered optimized with high-pressure homogenization. The optimized formulation was evaluated for its skin permeation efficiency. In vitro skin permeation studies were conducted with shaved BALB/c mice skin samples with a Franz diffusion cell system. Different drug concentrations were compared, and the effect of the nanoemulsion excipients on the permeation of the FITC-BSA was also studied.Results: The optimum homogenization regime was determined to be five passes at 20 000 psi, with no evidence of protein degradation during processing. With these conditions, the particle diameter was 85.2 nm ± 15.5 nm with a polydispersity index of 0.186 ± 0.026 and viscosity of 14.6 cP ± 1.2 cP. The optimized formulation proved stable for 1 year at 4 °C. In vitro skin diffusion studies show that the optimized formulation improves the permeation of FITC-BSA through skin with an enhancement ratio of 4.2 compared to a neat control solution. Finally, a comparison of the skin permeation of the nanoemulsion versus only the surfactant excipients resulted in a steady state flux of 23.44 μg/cm2/h for the nanoemulsion as opposed to 6.10 μg/cm2/h for the emulsifiers.Conclusion: A novel nanoemulsion with optimized physical characteristics and superior skin permeation compared to control solution was manufactured. The formulation proposed in this study has the flexibility for the incorporation of a variety of active ingredients and warrants further development as a transcutaneous vaccine delivery vehicle.

Release of a Wound-Healing Agent from PLGA Microspheres in a Thermosensitive Gel

The purpose of this research was to develop a topical microsphere delivery system in a thermosensitive 20% poloxamer 407 gel (Pluronic F127) to control release of KSL-W, a cationic antimicrobial decapeptide, for a period of 4–7 days for potential application in combat related injuries. KSL-W loaded microsphere formulations were prepared by a solvent extraction-evaporation method (water-oil-water), with poly (D,L-lactic-co-glycolic acid) (PLGA) (50 : 50, low-weight, and hydrophilic end) as the polymeric system. After optimization of the process, three formulations (A, B, and C) were prepared with different organic to water ratio of the primary emulsion while maintaining other components and manufacturing parameters constant. Formulations were characterized for surface morphology, porous nature, drug loading, in vitro drug release, and antimicrobial activity. Microspheres containing 20% peptide with porous surfaces and internal structure were prepared in satisfactory yields and in sizes varying from 25 to 50 μm. Gels of 20% Pluronic F127, which were liquid at or below 24.6°C and formed transparent films at body temperature, were used as carriers for the microspheres. Rheological studies showed a gelation temperature of 24.6°C for the 20% Pluronic F127 gel alone. Gelation temperature and viscosity of formulations A, B, and C as a function of temperature were very close to those of the carrier. A Franz diffusion cell system was used to study the release of peptide from the microspheres suspended in both, phosphate-buffered saline (PBS) and a 20% Pluronic F127 gel. In vitro release of greater than 50% peptide was found in all formulations in both PBS and the gel, and in one formulation there was a release of 75% in both PBS and the gel. Fractions collected from the release process were also tested for bactericidal activity against Staphylococcus epidermidis using the broth microdilution method and found to provide effective antimicrobial activity to warrant consideration and testing in animal wound models for treating combat-related injuries.